Fabric softening benefit obtained in the home is traditionally provided during the laundry cycle, either by using a rinse-added fabric softener that is added to the rinse cycle, or a dryer-added fabric softener, most commonly a dryer-added sheet, to be added to the dryer. Traditional rinse-added and dryer-added fabric softener products typically are used to treat a whole load of fabrics in the laundry cycle, e.g., in a washer or an automatic dryer. However, it is usually inconvenient and/or wasteful to soften a single or a few clothing items with this method. This is a frequent and common problem, when only one or two fabric items need to be washed. In such cases, the fabrics are usually washed by hand and line dried. Included to this category are delicate fabrics that need to be hand washed individually, and not to be dried in an automatic clothes dryer. The hand-washed and line-dried fabric items usually feel coarse and harsh, unlike the items that are machine washed and/or dried in an automatic clothes dryer.
Most consumer rinse-added fabric softener and dryer-added fabric softener compositions contain dialkyl and/or alkenyl quaternary ammonium salts as the main fabric softening active. Examples of quaternary ammonium fabric softening actives are disclosed in U.S. Pat. No. 3,861,870, Edwards et al.; U.S. Pat. No. 4,308,151, Cambre; U.S. Pat. No. 3,886,075, Bernardino; U.S. Pat. No. 4,233,164, Davis; U.S. Pat. No. 4,401,578, Verbruggen; U.S. Pat. No. 3,974,076, Wiersema et al.; and U.S. Pat. No. 4,237,016, Rudkin et al. Some preferred quaternary ammonium fabric softening active systems are disclosed in U.S. Pat. No. 4,661,269, issued Apr. 28, 1987, to T. Trinh et al.; U.S. Pat. No. 5,545,340, issued Aug. 13, 1996, to Wahl et al.; U.S. Pat. No. 5,747,443 issued May 5, 1998 to E. H. Wahl et al.; and U.S. Pat. No. 5,830,845 issued Nov. 3, 1998 to T. Trinh et al. Examples of dryer-added fabric softener actives are given in U.S. Pat. No. 6,046,154 issued Apr. 4, 2000 to Trinh et al.; other dryer-added fabric softener actives can be found in U.S. Pat. Nos. 4,327,133; 4,421,792; 426,299; 4,460,485; 3,644,203; 4,661,269; 4,439,335; 3,861,870; 4,308,151; 3,886,075; 4,233,164; 4,401,578; 3,974,076; 4,237,016 and EP 472,17.
Alternative actives have been suggested, such as silicones, due to their lubricity. Silicones can be used in liquid fabric softener compositions to provide additional fabric feel, as is disclosed in U.S. Pat. No. 4,855,072 issued Aug. 8, 1989 to Trinh et al, said patent being incorporated herein by reference. The preferred silicones are polydimethylsiloxanes that can be incorporated into the softener compositions as a neat fluid, or can be added in a preemulsified form which is available from many suppliers. Examples of these preemulsified silicones are a 60% emulsion of polydimethylsiloxane (350 cs) from Dow Corning Corporation under the trade name DOW CORNING® 1157 Fluid, and a 50% emulsion of polydimethylsiloxane (10,000 cs) from General Electric Company under the trade name General Electric® SM 2140 Silicones. In order to increase fabric substantivity of the silicones to improve fabric feel, the silicones can be derivatised with cationic groups, such as those disclosed in U.S. Pat. No. 5,098,979 issued Mar. 24, 1992 and U.S. Pat. No. 5,196,499 issued Mar. 23, 1993, both to O'Lenick, Jr., or the silicones can be derivatised with reactive, curable groups that can condense to form higher molecular weight silicones, such as those disclosed in U.S. Pat. No. 4,419,391 issued Dec. 6, 1983 to Tanaka et al., all said patents are incorporated herein by reference.
It is well known that after treated several times with rinse-added fabric softener products and/or dryer-added fabric softener products, the cotton fabrics become somewhat waterproof, and become less water absorbent. This is because the common fabric softener actives are substantive to fabrics.
The silicones can also be derivatised with hydrophilic groups, to make them able to self-emulsify and/or to provide surface activity. The most common silicones of this class are the polyalkyleneoxy polysiloxanes. Commercial literature on polyalkyleneoxy polysiloxanes, such as “Silwet® Surfactants”, OS-144 6/94-10M, published by OSi Specialties, Inc., discloses that some of the polyalkyleneoxy polysiloxanes add softness to fabrics, and that the softness property increases with the percent silicone in the polyalkyleneoxy polysiloxanes.
Although many of the fabric softener actives have been disclosed as having softening activity, there has been no characterization of which softener actives are most effective and/or preferred in the context of a product which is sprayed onto the fabrics as opposed to being deposited in the rinse and/or washing steps from a highly dilute aqueous bath. The art has not considered what is the optimum softener when there is no competition between the fabrics and the aqueous bath.
In one aspect the present invention relates to stable, preferably translucent, more preferably clear, aqueous fabric softening compositions comprising polyalkyleneoxy polysiloxanes which comprise at least some ethyleneoxy units, articles of manufacture comprising said compositions and/or method for use of said compositions on fabrics, preferably by direct application of said compositions on fabrics. Preferably, the compositions are used by the consumer to spray onto fabrics, particularly clothes, one at a time, to conveniently provide fabric softening benefit, without having to treat the whole load of fabrics in a washer and/or dryer, and/or without having to iron the fabrics. Cotton fabrics treated with the composition of the present invention do not become waterproof and synthetic fabrics can become more water absorbent. The articles of manufacture of the present invention preferably are packaged in association with instructions for use to direct the consumer to use the composition to treat fabrics correctly, including, e.g., the manner and/or amount of composition to spray, e.g., to apply an effective amount of the fabric softening composition and/or polyethyleneoxy polysiloxane to the fabric, to provide the fabric softening benefit, without the need of using the traditional rinse-added or dryer-added softener products and/or ironing. The fabric softening actives of the present invention can readily be washed off the fabrics. The aqueous fabric softening compositions of the present invention contain polyalkyleneoxy polysiloxanes as a key softening actives. However, it is found that in the context of the aqueous fabric softening compositions of the present invention, that are designed for direct application on fabrics, contrary to the teaching in the Silwet® Surfactants literature, the percent silicone alone correlates very poorly with the fabric softening performance of the spray compositions. Instead, it is discovered, using a quantitative structure-activity relationship (QSAR) approach, that the fabric softening performance of the compositions of the present invention depends on a combination of several properties of the polyalkyleneoxy polysiloxanes including the average total number of SiMe2O units in the molecule, the average total number of ethyleneoxy CH2CH2O units in the molecule, and the % silicone.
The compositions of the present invention can provide other fabric care benefits, such as, wrinkle removal, wrinkle reduction, fabric color restoration, and/or fabric color rejuvenation, and when optional ingredients are present, the compositions can optionally provide other fabric care benefits, such as malodor control, static control, antibacterial action, insect repellency, and the like, as well as a “scent signal” in the form of a pleasant odor, and combinations thereof.